#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
#include "llvm/Constant.h"
#include "llvm/Type.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Support/ValueHandle.h"
#include <algorithm>
using namespace llvm;
/// DeleteDeadBlock - Delete the specified block, which must have no
/// predecessors.
void llvm::DeleteDeadBlock(BasicBlock *BB) {
- assert(pred_begin(BB) == pred_end(BB) && "Block is not dead!");
+ assert((pred_begin(BB) == pred_end(BB) ||
+ // Can delete self loop.
+ BB->getSinglePredecessor() == BB) && "Block is not dead!");
TerminatorInst *BBTerm = BB->getTerminator();
// Loop through all of our successors and make sure they know that one
BB->eraseFromParent();
}
+/// FoldSingleEntryPHINodes - We know that BB has one predecessor. If there are
+/// any single-entry PHI nodes in it, fold them away. This handles the case
+/// when all entries to the PHI nodes in a block are guaranteed equal, such as
+/// when the block has exactly one predecessor.
+void llvm::FoldSingleEntryPHINodes(BasicBlock *BB) {
+ if (!isa<PHINode>(BB->begin()))
+ return;
+
+ while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) {
+ if (PN->getIncomingValue(0) != PN)
+ PN->replaceAllUsesWith(PN->getIncomingValue(0));
+ else
+ PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
+ PN->eraseFromParent();
+ }
+}
+
+
+/// DeleteDeadPHIs - Examine each PHI in the given block and delete it if it
+/// is dead. Also recursively delete any operands that become dead as
+/// a result. This includes tracing the def-use list from the PHI to see if
+/// it is ultimately unused or if it reaches an unused cycle. If a
+/// ValueDeletionListener is specified, it is notified of the deletions.
+void llvm::DeleteDeadPHIs(BasicBlock *BB, ValueDeletionListener *VDL) {
+ // Recursively deleting a PHI may cause multiple PHIs to be deleted
+ // or RAUW'd undef, so use an array of WeakVH for the PHIs to delete.
+ SmallVector<WeakVH, 8> PHIs;
+ for (BasicBlock::iterator I = BB->begin();
+ PHINode *PN = dyn_cast<PHINode>(I); ++I)
+ PHIs.push_back(PN);
+
+ for (unsigned i = 0, e = PHIs.size(); i != e; ++i)
+ if (PHINode *PN = dyn_cast_or_null<PHINode>(PHIs[i].operator Value*()))
+ RecursivelyDeleteDeadPHINode(PN, VDL);
+}
+
/// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor,
/// if possible. The return value indicates success or failure.
bool llvm::MergeBlockIntoPredecessor(BasicBlock* BB, Pass* P) {
// Finally, erase the old block and update dominator info.
if (P) {
- if (DominatorTree* DT = P->getAnalysisToUpdate<DominatorTree>()) {
+ if (DominatorTree* DT = P->getAnalysisIfAvailable<DominatorTree>()) {
DomTreeNode* DTN = DT->getNode(BB);
DomTreeNode* PredDTN = DT->getNode(PredBB);
BasicBlock *New = Old->splitBasicBlock(SplitIt, Old->getName()+".split");
// The new block lives in whichever loop the old one did.
- if (LoopInfo* LI = P->getAnalysisToUpdate<LoopInfo>())
+ if (LoopInfo* LI = P->getAnalysisIfAvailable<LoopInfo>())
if (Loop *L = LI->getLoopFor(Old))
L->addBasicBlockToLoop(New, LI->getBase());
- if (DominatorTree *DT = P->getAnalysisToUpdate<DominatorTree>())
+ if (DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>())
{
// Old dominates New. New node domiantes all other nodes dominated by Old.
DomTreeNode *OldNode = DT->getNode(Old);
DT->changeImmediateDominator(*I, NewNode);
}
- if (DominanceFrontier *DF = P->getAnalysisToUpdate<DominanceFrontier>())
+ if (DominanceFrontier *DF = P->getAnalysisIfAvailable<DominanceFrontier>())
DF->splitBlock(Old);
return New;
Preds[i]->getTerminator()->replaceUsesOfWith(BB, NewBB);
// Update dominator tree and dominator frontier if available.
- DominatorTree *DT = P ? P->getAnalysisToUpdate<DominatorTree>() : 0;
+ DominatorTree *DT = P ? P->getAnalysisIfAvailable<DominatorTree>() : 0;
if (DT)
DT->splitBlock(NewBB);
- if (DominanceFrontier *DF = P ? P->getAnalysisToUpdate<DominanceFrontier>():0)
+ if (DominanceFrontier *DF = P ? P->getAnalysisIfAvailable<DominanceFrontier>():0)
DF->splitBlock(NewBB);
- AliasAnalysis *AA = P ? P->getAnalysis
ToUpdate<AliasAnalysis>() : 0;
+ AliasAnalysis *AA = P ? P->getAnalysis
IfAvailable<AliasAnalysis>() : 0;
// Insert a new PHI node into NewBB for every PHI node in BB and that new PHI
return NewBB;
}
+/// FindFunctionBackedges - Analyze the specified function to find all of the
+/// loop backedges in the function and return them. This is a relatively cheap
+/// (compared to computing dominators and loop info) analysis.
+///
+/// The output is added to Result, as pairs of <from,to> edge info.
+void llvm::FindFunctionBackedges(const Function &F,
+ SmallVectorImpl<std::pair<const BasicBlock*,const BasicBlock*> > &Result) {
+ const BasicBlock *BB = &F.getEntryBlock();
+ if (succ_begin(BB) == succ_end(BB))
+ return;
+
+ SmallPtrSet<const BasicBlock*, 8> Visited;
+ SmallVector<std::pair<const BasicBlock*, succ_const_iterator>, 8> VisitStack;
+ SmallPtrSet<const BasicBlock*, 8> InStack;
+
+ Visited.insert(BB);
+ VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
+ InStack.insert(BB);
+ do {
+ std::pair<const BasicBlock*, succ_const_iterator> &Top = VisitStack.back();
+ const BasicBlock *ParentBB = Top.first;
+ succ_const_iterator &I = Top.second;
+
+ bool FoundNew = false;
+ while (I != succ_end(ParentBB)) {
+ BB = *I++;
+ if (Visited.insert(BB)) {
+ FoundNew = true;
+ break;
+ }
+ // Successor is in VisitStack, it's a back edge.
+ if (InStack.count(BB))
+ Result.push_back(std::make_pair(ParentBB, BB));
+ }
+
+ if (FoundNew) {
+ // Go down one level if there is a unvisited successor.
+ InStack.insert(BB);
+ VisitStack.push_back(std::make_pair(BB, succ_begin(BB)));
+ } else {
+ // Go up one level.
+ InStack.erase(VisitStack.pop_back_val().first);
+ }
+ } while (!VisitStack.empty());
+
+
+}
+
+
+
/// AreEquivalentAddressValues - Test if A and B will obviously have the same
/// value. This includes recognizing that %t0 and %t1 will have the same
/// value in code like this:
-/// %t0 = getelementptr @a, 0, 3
+/// %t0 = getelementptr \@a, 0, 3
/// store i32 0, i32* %t0
-/// %t1 = getelementptr @a, 0, 3
+/// %t1 = getelementptr \@a, 0, 3
/// %t2 = load i32* %t1
///
static bool AreEquivalentAddressValues(const Value *A, const Value *B) {
}
while (ScanFrom != ScanBB->begin()) {
+ // We must ignore debug info directives when counting (otherwise they
+ // would affect codegen).
+ Instruction *Inst = --ScanFrom;
+ if (isa<DbgInfoIntrinsic>(Inst))
+ continue;
+ // We skip pointer-to-pointer bitcasts, which are NOPs.
+ // It is necessary for correctness to skip those that feed into a
+ // llvm.dbg.declare, as these are not present when debugging is off.
+ if (isa<BitCastInst>(Inst) && isa<PointerType>(Inst->getType()))
+ continue;
+
+ // Restore ScanFrom to expected value in case next test succeeds
+ ScanFrom++;
+
// Don't scan huge blocks.
if (MaxInstsToScan-- == 0) return 0;
- Instruction *Inst = --ScanFrom;
-
+ --ScanFrom;
// If this is a load of Ptr, the loaded value is available.
if (LoadInst *LI = dyn_cast<LoadInst>(Inst))
if (AreEquivalentAddressValues(LI->getOperand(0), Ptr))
// block.
return 0;
}
+
+/// CopyPrecedingStopPoint - If I is immediately preceded by a StopPoint,
+/// make a copy of the stoppoint before InsertPos (presumably before copying
+/// or moving I).
+void llvm::CopyPrecedingStopPoint(Instruction *I,
+ BasicBlock::iterator InsertPos) {
+ if (I != I->getParent()->begin()) {
+ BasicBlock::iterator BBI = I; --BBI;
+ if (DbgStopPointInst *DSPI = dyn_cast<DbgStopPointInst>(BBI)) {
+ CallInst *newDSPI = DSPI->clone();
+ newDSPI->insertBefore(InsertPos);
+ }
+ }
+}
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